Combined gas trap and liquid separator

ABSTRACT

The invention contemplates an improved steam trap of the inverted-bucket type, providing the function of separating liquid from gas in a given inlet-fluid flow, without substantial impairment of the gas flow. In steam applications, condensate is separated and passed off as necessary, allowing a continuous flow of steam via a steam outlet which is independent of a condensate outlet. The separation of steam from condensate is achieved by using an inlet-fluid conduit which discharges into and within the bucket at an elevation less than that of the upper end of a gasoutlet conduit which is also within the bucket; by selecting the size of the gas-outlet conduit so as to provide a slight constriction to the gas (steam) flow, the bucket will be buoyed to a degree reflecting gas vs. liquid volumes within the trap. Discharge of separated condensate liquid is via a valve operated by the extent of buoyed elevation of the bucket, and discharge of separated steam is independent of whether or not condensate is being discharged.

nite

Asfura States Patent 1191 1451 Oct. 22, 1974 1541 COMBINED GAS TRAP AND LIQUID SEPARATOR [221 Fned; Jan. 1o, 1973 [21] Appl. NQ; 322,491

[30] Foreign Application Priority Data Aug. 14,1972 'Mexico 137745 [52] U.S. Cl. 137/179, 137/185 [51] Int. Cl Fl6t 1/30 [58] Field of Search 137/179, 181, 185, 186, l 137/180 [56] References Cited UNITED STATES PATENTS 118,786 9/1871 Bundy 137/181 452,128 5/1891 Funke 137/181 1,624,446 4/1927 Templetonm. 137/180 1,766,970 6/1930 Armstrong... 137/185 2,003,069 5/1935 Carter 137/179 2,586,143 2/1952 Baker etal... 137/185 2,955,611 10/1960 ,Shimizu 137/185 FOREIGN PATENTS OR APPLlCATIONS 109,381 4/1928 Austria 285/133 R Primary Examner-William R. Cline Assistant Examiner-Gerald A. Michalsky Attorney, Agent, or Firm-Sandoe, Hopgood and Calimafde [5 7 l ABSTRACT The invention contemplates an improved steam trap of the inverted-bucket type, providing the function of separating liquid from gas in a given inlet-fluid flow, without substantial impairment of the gas tlow. In steam applications, condensate is separated and passed off as necessary, allowing a continuous flow of steam via a steam outlet which is independent of a condensate outlet. The separation of steam from condensate is achieved by using an inlet-fluid conduit which discharges into and within the bucket at an elevation less than that of the upper end of a gas-outlet conduit which is also within the bucket; by selecting the size of the gas-outlet conduit so as to provide a slight constriction to the gas (steam) flow, the bucket will be buoyedV tQ deesse tegtisns assays: liquidorvQl: umes within the trap. Discharge of separated condensate liquid is via a valve operated by the extent of buoyed elevation of the bucket, and discharge of separated steam is independent of whether or not condensate is being discharged.

9 Claims, 2 Drawing Figures COMBINED GAS TRAP AND LIQUID SEPARATOR BACKGROUND OF THE INVENTION The inverted-bucket type steam traps improved by the device claimed here is very well known. Their operation is based on the difference in density between steam and condensate, as explained in the following paragraphs.

Based on the fact that the trap body or chamber always contains a certain amount of water, the inverted bucket will have more or less buoyancy depending on what is inside of it, steam or condensate. With this in rnind, the operation can be described as follows:

When steam enters at the bottom of the trap, or through the stabilizing tube, it is trapped inside of the bucket, since the latter is sealed in water. The low steam density causes an increase in buoyancy of the bucket, which rises, carrying along the lever that contains the valve.

The raising of the lever makes the valve contact the valve seat, thus closing the outlet of the trap.

When condensate enters, due to its higher density, it fills the inside of the bucket, increasing the bucket weight and causing it to sink in the water; this action lowers the lever and with it the valve, which latter opens the valve seat and allows the trap to discharge.

Non-condensable gases, whenever they reach the trap, escape through a small orifice on the top of the bucket and accumulate on the upper part of the trap until the trap opens, and they are discharged along with the condensate.

Since the trap inlet is always connected, through piping, to the equipment being drained, the trap body or chamber is always under pressure; this helps to discharge condensates when the trap opens.

Although the above described steam trap is generally considered as the most efficient, it has the disadvantage that it can not differentiate between live and flash steam; it will always close on either one. Moreover, if compressed air is piped into the trap, it will also close because, as described before, all of the three above fluids have less density than condensate and, therefore, they all cause the bucket to float and close the trap.

SUMMARY OF THE INVENTION There is provided here a device for extracting steam and non-condensable gases from the inside of the inverted bucket in the trap as the one described above, improving its operation and increasing its functions beyond those of a steam trap because, besides the normal steam trap functions, it separates steam and condensates, and through different outlets allows them to be piped in separate tubes, conducting the condensates to the boiler room and permitting re-use of the extracted steam. The improvement fulfills three other main purposes:

l. To prevent closing of the trap because of flash steam. The extraction tube extracts this flash steam from inside the bucket, before it causes the bucket to rise. (It must be remembered that flash steam is but a small percentage of the total condensate flow. Although this small flash steam flow can be discharged though the extraction tube, it is enough to cause the bucket to rise and close the trap, if not extracted).

2. To extract non-condensable gases from inside the equipment drained by the trap. Non-condensable gases, commonly air and carbon dioxide, get into the boiler dissolved in the water; as this evaporates, they are liberated along with the steam. However, when steam condenses, these gases do not dissolve again and they must be removed because they not only do not transfer heat, but because they form an insulating barrier to heat transmission.

An ordinary steam trap can not extract these noncondensable gases efficiently because it only opens in the presence of condensate. With the addition of the continuous extraction device, there is a constant f'low of steam and non-condensable gases, even though the trap may be closed. This means that some live steam is extracted before it transfers its heat, but the increase in the performance of the equipment more than upsets the apparent steam waste.

3. To increase the velocity of fluids to the trap. Because the extraction device is continuously drawing out steam and gases, it is creating a flow velocity towards the trap. This velocity increases heat transmission, because it has a scrubbing action on the walls of the equipment being drained; this scrubbing destroys the air and non-condensable gas film. The destruction of the film increases the flow of heat across the walls of the equipment.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an inverted bucket steam trap, modified by an inventive steam and gases extraction device, showing the main component parts both internal and external; and

FIG. 2 is also a sectional view of the steam trap but with a different mode of installation.

The trap is made of a hollow body 11, defining an internal chamber l2 which has a cap or cover 13 shaped like an inverted cup and connected to the internal chamber 12 by means of bolts across bores l5. In a closing wall 14, there is a valve outlet 16 and a valve seat 17 located on the side of the wall 14 adjacent to the internal chamber 12. Inside of the chamber 12, there is an inverted bucket 18 which has on its top a fixed hook 34 which serves to either push or pull a lever 19 containing a valve 20.

The hollow body 11 has in its lower part a concentric central annular boss 21 with an inside thread 22 to receive a stabilizing tube 23 which projects vertically up into the chamber 12, but without reaching the top of the bucket 18.

A threaded nipple 24 is connected to an internal thread 25 of a condensate inlet 26 to the hollow body 11. Said nipple serves to connect a fitting 27 containing an internal, substantially annular chamber 28 to which the steam, gases and condensate enter through an opening 29. A special coupling 30 with external thread connects to fitting 27 and through the internal thread to an extraction tube 31, which, on its other end, projects vertically above the stabilizing tube 23, almost reaching, but not touching the top of the invertedr bucket 18.

Optionally, a deflector plate can be installed on the top of the extraction tube 31; this deflector plate serves the purpose of preventing the condensate to enter the extraction tube 31. Y

The outlet of coupling 30, coming out of the extrac. tion tube 31 can be discharged, as shown, in FIG. 1,

through a discharge pipe having therein an orifice 32 to the atmosphere or, as shown in FIG. 2, through a valve 36 (or through an orifice), to the condensate discharge pipe 33 or, it can also discharge, either through a valve or an orifice, to a different pipe which will collect the extraction steam and conduct it where it can be used.

The invention has been described according to its normal character of usage, but it should be understood and established that any variation made to the mentioned steam trap, based on what has been described, necessarily falls within the scope of the invention. It is also established that any variation in shape or materials of construction, of any part of the device or trap, do not change the spirit or scope of the invention.

l claim:

l. A combined gas trap and liquid separator, comprising a hollow body including a cover and defining an internal chamber, an inverted bucket vertically movable inside said chamber, said cover having an outlet opening for liquid discharge from said chamber, means including a lever movably connecting said bucket to a part of said body, a valve operated by said lever and determining the closed condition of the outlet opening for a predetermined elevated position of said bucket, and determining an open condition of the outlet opening for bucket elevations below said position, an inlet connection for admitting fluid and comprising a first fixed conduit extending upwardly within said bucket to an elevation which is substantially offset from the upper end of said bucket and which is within said bucket for all possible bucket positions, and a gas-extraction outlet connection including a second fixed conduit extending upwardly within the bucket to an elevation which has a lesser offset from the upper end of said bucket, said second conduit extending externally of said body and inlet connection for conduct of extracted gas; whereby the difference in elevation for the respective offsets of said conduits from the upper end of said bucket serves to isolate vapor from liquid and to assure discharge of vapor substantially free of liquid in said second conduit, regardless of the extent to which the bucket may be called upon to buoyantly actuate said valve to control liquid discharge via the opening in said cover.

2. The trap and separator of claim 1, in which the discharge of the inlet-f`luid conduit is disposed symmetrically with respect to the central axis of the bucket.

3. The trap and separator of claim 2, in which the discharge end of the inlet-fluid conduit is tubular and coaxially surrounds the gas-outlet conduit, the gas-outlet conduit having its inlet positioned above the upper tubular end of the inlet-fluid conduit.

4. The trap and separator of claim l, in which bleed means in the upper end of the inverted bucket provides restricted venting of the upper end of the bucket to the upper region of said chamber.

5. The trap and separator as defined in claim 1, wherein said discharge end of the extraction conduit has therein a restricted orifice open to the atmosphere.

6. The trap and separator as defined in claim 1, further comprising another valve between the discharge end of the extraction conduit and the atmosphere.

7. The trap and separator as defined in claim 1, wherein the discharge end of the extraction conduit connects to a condensate discharge pipe.

8. The trap and separator as defined in claim l, wherein the discharge end of the extraction conduit connects to another pipe.

9. The trap and separator as defined in claim 1, further comprising a fitting connected to an inlet of the trap body, and inside which is connected said extraction conduit, said fitting defining an annular space for the admission of inlet fluid.

i =i s i 

1. A combined gas trap and liquid separator, comprising a hollow body including a cover and defining an internal chamber, an inverted bucket vertically movable inside said chamber, said cover having an outlet opening for liquid discharge from said chamber, means including a lever movably connecting said bucket to a part of said body, a valve operated by said lever and determining the closed condition of the outlet opening for a predetermined elevated position of said bucket, and determining an open condition of the outlet opening for bucket elevations below said position, an inlet connection for admitting fluid and comprising a first fixed conduit extending upwardly within said bucket to an elevation which is substantially offset from the upper end of said bucket and which is within said bucket for all possible bucket positions, and a gas-extraction outlet connection including a second fixed conduit extending upwardly within the bucket to an elevation which has a lesser offset from the upper end of said bucket, said second conduit extending externally of said body and inlet connection for conduct of extracted gas; whereby the difference in elevation for the respective offsets of said conduits from the upper end of said bucket serves to isolate vapor from liquid and to assure discharge of vapor substantially free of liquid in said second conduit, regardless of the extent to which the bucket may be called upon to buoyantly actuate said valve to control liquid discharge via the opening in said cover.
 2. The trap and separator of claim 1, in which the discharge of the inlet-fluid conduit is disposed symmetrically with respect to the central axis of the bucket.
 3. The trap and separator of claim 2, in which the discharge end of the inlet-fluid conduit is tubular and coaxially surrounds the gas-outlet conduit, the gas-outlet conduit having its inlet positioned above the upper tubular end of the inlet-fluid conduit.
 4. The trap and separator of claim 1, in which bleed means in the upper end of the inverted bucket provides restricted venting of the upper end of the bucket to the upper region of said chamber.
 5. The trap and separator as defined in claim 1, wherein said discharge end of the extraction conduit has therein a restricted orifice open to the atmosphere.
 6. The trap and separator as defined in claim 1, further comprising another valve between the discharge end of the extraction conduit and the atmosphere.
 7. The trap and separator as defined in claim 1, wherein the discharge end of the extraction conduit connects to a condensate discharge pipe.
 8. The trap and separator as defined in claim 1, wherein the discharge end of the extraction conduit connects to another pipe.
 9. The trap and separator as defined in claim 1, further comprising a fitting connected to an inlet of the trap body, and inside which is connected said extraction conduit, said fitting defining an annular space for the admission of inlet fluid. 